If a TCP socket will get live-migrated from one box to another the
timestamps (which are typically ON) will get screwed up -- the new
kernel will generate TS values that has nothing to do with what they
were on dump. The solution is to yet again fix the kernel and put a
"timestamp offset" on a socket.
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Alexey Kuznetsov <kuz...@ms2.inr.ac.ru>
Cc: James Morris <jmor...@namei.org>
Cc: Hideaki YOSHIFUJI <yoshf...@linux-ipv6.org>
Cc: Patrick McHardy <ka...@trash.net>
Cc: Eric Dumazet <eduma...@google.com>
Cc: Yuchung Cheng <ych...@google.com>
Cc: Neal Cardwell <ncardw...@google.com>
Cc: Pavel Emelyanov <xe...@parallels.com>
Cc: Dave Jones <da...@redhat.com>
Cc: Michael Kerrisk <mtk.manpa...@gmail.com>
Signed-off-by: Andrey Vagin <ava...@openvz.org>
---
include/linux/tcp.h | 2 ++
include/uapi/linux/tcp.h | 1 +
net/ipv4/tcp.c | 6 ++++++
net/ipv4/tcp_output.c | 7 ++++---
4 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 4e1d228..746dad5 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -162,6 +162,8 @@ struct tcp_sock {
u32 rcv_tstamp; /* timestamp of last received ACK (for
keepalives) */
u32 lsndtime; /* timestamp of last sent data packet (for
restart window) */
+ u32 snd_tsval_offset; /* offset for snd_tsval */
+
struct list_head tsq_node; /* anchor in tsq_tasklet.head list */
unsigned long tsq_flags;
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index e962faa..6b1ead0 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -111,6 +111,7 @@ enum {
#define TCP_QUEUE_SEQ 21
#define TCP_REPAIR_OPTIONS 22
#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */
+#define TCP_TIMESTAMP 24
struct tcp_repair_opt {
__u32 opt_code;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1ca2536..72dee28 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2704,6 +2704,9 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
else
err = -EINVAL;
break;
+ case TCP_TIMESTAMP:
+ tp->snd_tsval_offset = val - tcp_time_stamp;
+ break;
default:
err = -ENOPROTOOPT;
break;
@@ -2952,6 +2955,9 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
case TCP_USER_TIMEOUT:
val = jiffies_to_msecs(icsk->icsk_user_timeout);
break;
+ case TCP_TIMESTAMP:
+ val = tcp_time_stamp + tp->snd_tsval_offset;
+ break;
default:
return -ENOPROTOOPT;
}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 5d45159..9b6d485 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -622,7 +622,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct
sk_buff *skb,
if (likely(sysctl_tcp_timestamps && *md5 == NULL)) {
opts->options |= OPTION_TS;
- opts->tsval = TCP_SKB_CB(skb)->when;
+ opts->tsval = TCP_SKB_CB(skb)->when + tp->snd_tsval_offset;
opts->tsecr = tp->rx_opt.ts_recent;
remaining -= TCPOLEN_TSTAMP_ALIGNED;
}
@@ -705,6 +705,7 @@ static unsigned int tcp_synack_options(struct sock *sk,
struct tcp_extend_values *xvp,
struct tcp_fastopen_cookie *foc)
{
+ struct tcp_sock *tp = tcp_sk(sk);
struct inet_request_sock *ireq = inet_rsk(req);
unsigned int remaining = MAX_TCP_OPTION_SPACE;
u8 cookie_plus = (xvp != NULL && !xvp->cookie_out_never) ?
@@ -739,7 +740,7 @@ static unsigned int tcp_synack_options(struct sock *sk,
}
if (likely(ireq->tstamp_ok)) {
opts->options |= OPTION_TS;
- opts->tsval = TCP_SKB_CB(skb)->when;
+ opts->tsval = TCP_SKB_CB(skb)->when + tp->snd_tsval_offset;
opts->tsecr = req->ts_recent;
remaining -= TCPOLEN_TSTAMP_ALIGNED;
}
@@ -806,7 +807,7 @@ static unsigned int tcp_established_options(struct sock
*sk, struct sk_buff *skb
if (likely(tp->rx_opt.tstamp_ok)) {
opts->options |= OPTION_TS;
- opts->tsval = tcb ? tcb->when : 0;
+ opts->tsval = tcb ? tcb->when + tp->snd_tsval_offset : 0;
opts->tsecr = tp->rx_opt.ts_recent;
size += TCPOLEN_TSTAMP_ALIGNED;
}
--
1.7.11.7
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